作者:Martin Sczepan、Wolfgang Rettig、A. I. Tolmachev、V. V. Kurdyukov
DOI:10.1039/b102779b
日期:——
The synthesis of selectively bridged stilbazolium dyes related to DASPMI is described. The comparison of steady-state and time-resolved fluorescence studies as a function of temperature allows one to develop a kinetic model on the basis of which the high photostability and absence of photoisomerization for these dyes can be understood. There are two possible photochemical deactivation channels: non-radiative decay through single-bond twisting which does not lead to a distinguishable photoisomer and through double bond twisting leading to trans–cis photoisomerization. The latter process is more than one order of magnitude slower than single-bond
twisting for these compounds and is only observed in the compound where both single bonds are bridged. Lifetime maxima observed at low temperature indicate a further early structural relaxation not connected with bond twisting but with bond length changes.
描述了与DASPMI相关的选择性桥联的斯蒂尔巴唑铵染料的合成。温度作为函数的稳态和时间分辨荧光研究的比较使人们能够建立一个动力学模型,基于该模型可以理解这些染料的高光稳定性和缺乏光异构化。存在两种可能的光化学去激发通道:通过单键扭转的非辐射衰减,不会导致可区分的光异构体,以及通过双键扭转导致的反–顺光异构化。对于这些化合物,后者的过程比单键扭转慢超过一个数量级,并且仅在两个单键都被桥接的化合物中观察到。在低温下观察到的寿命最大值表明,存在一种与键扭转无关但与键长变化相关的早期结构松弛过程。